Is that LED blinking?

This is an odd question, but it has been bugging me for years and I figure if any group of people would know about it, you guys would.

I've worked for at least two different companies that used AT&T's Audix voice-mail system. They all shared a common, regular looking model of touch-tone phone with one exception beyond the ordinary - a red LED next to the keypad that blinks when you have new voicemail.

The thing is, that these LEDs often appear to blink when there is no new voicemail and when you look at them out of the corner of your eye. But, if you actively watch for the blink, even forcing yourself to use the corner of your eye, you never see it. It only happens when you aren't paying attention to the phone. I know about rods and cones and how the eye is tuned to sense motion on the peripherary and color in the center, etc, etc. So that makes me think these phones really are spontaneously blinking when they shouldn't be. Plus, I'm not the only one to experience this phenomena at these companies.

So, my question is, does anyone know FOR SURE if these Audix phone LEDs spontaneously blink when they should not be doing so? And, any idea for verifying the blink is really happening short of tearing the phone apart or using a high speed video camera or something extreme like that?

I don't know about those particular phones, but it is possible the LED is strobing at 60Hz which is the standard frequency for AC power in the US. I've noticed this with an LED nightlight I have. You're right about only noticing it out of the corner of your eye. There must be more persistence of vision towards the center.

I think it's 60 Hz. The one on the phone annoys me because I think I have a msg. When I'm in a dimly lit room with such a LED and I move my head, I see a series of dots in a row in the corner of my eye.

When I walk through the garage at night I see a series of green dots. No doubt from the green LED on the garage door opener.

It's possible that it "blinks" when the software polls your mailbox to see if new mail is added. Try watching it at the top of the hour or at the stroke of midnight...